Correlation between RIA-EIA-ELISA methods for alpha-fetoprotein research

To-day, the possibility of researching alpha-fetoprotein is given not only by the RIA method but also some immunoenzymatic methods. The Authors have compared three types of methods: RIA, EIA and ELISA, and have also studied the correlation coefficient in 30 samples. Method in solid phase (coated-tubes) and mouse monoclonal antibodies are used for the radioimmunologic method. The ELISA method utilizes two monoclonal antibodies: the former is coated to the walls of the test tubes (mouse monoclonal antibodies) and the latter is labelled with bovine alkaline phosphatase. The EIA methods is a solid phase enzyme immunoassay based on the sandwich principle. It consists of beads coated of goat antibodies and goat anti-AFP antibodies conjugated with horseradish peroxidase. The correlation coefficient is: RIA-ELISA = r 0.95; RIA-EIA = r 0.93; EIA-ELISA = r 0.96. The correlation coefficient from both the RIA method (taken as a reference) and the immunoenzymatic methods is good, so that the passage from RIA to enzymatic methods is possible without problems of under or above dosage of alpha-fetoprotein values.